Various types of pressure sensors to determine the pressure of a medium engaging a wall, typically a fluid, and especially a liquid medium, are known. Pressure sensing elements which determine such pressure may use an electrical resistance element which is subjected to the medium, the pressure of which is to be determined, and which changes its electrical resistance in dependence on the pressure applied thereon. Such resistance elements, as such, are known. Other types of sensors are known in which the resistance element is formed as a layer or film structure which is secured to an individual carrier. For example, German Patent Disclosure Document DE-OS No. 31 25 640 describes a sensor which changes its resistance upon being subjected to pressure, and in which a base structure is used carrying two electrical supply lines leading through the wall on which the resistance element itself is secured. The resistance element itself is a film or layertype resistor extending between two ends of the respective connecting or supply lines. The resistance element is secured to a metallic base structure which surrounds an insulating material mass through which the supply lines extend and which, in turn, projects towards the end of the base structure up to the pressure region, typically a pressure chamber. The described sensor, thus, has a layer resistor secured to a carrier which is located at the pressure side of a structural element receiving a casting compound of insulating material and which has elastic or yielding characteristics, and through which the connecting lines for the layer resistors are conducted.
It has been found that the insulating material on which the layer resistor is applied does not have the required mechanical strength to withstand high pressures, and especially high hydraulic pressures, to be able to function as a support for a layer resistor. Upon application of very high pressures, the continuity of the layer resistor may be impaired.